Implications of the dimuon CP asymmetry in B_{d,s} decays

TL;DR

This paper analyzes the dimuon CP asymmetry in B_{d,s} decays, showing that new physics could explain the deviation from the Standard Model without relying on certain theoretical calculations, and finds that a minimal flavor violation framework can account for the observations.

Contribution

It introduces a model-independent analysis of B_{d,s} mixing data that accommodates new physics contributions and demonstrates the viability of minimal flavor violation with CP phases.

Findings

Good fit to all measurements including CDF S_{ψφ}

Universal new physics contributions in B_d and B_s systems are possible

Larger deviations are favored in B_s mixing

Abstract

The D0 Collaboration reported a 3.2sigma deviation from the standard model prediction in the like-sign dimuon asymmetry. Assuming that new physics contributes only to B_{d,s} mixing, we show that the data can be analyzed without using the theoretical calculation of \Delta\Gamma_s, allowing for robust interpretations. We find that this framework gives a good fit to all measurements, including the recent CDF S_{\psi\phi} result. The data allow universal new physics with similar contributions relative to the SM in the B_d and B_s systems, but favors a larger deviation in B_s than in B_d mixing. The general minimal flavor violation framework with flavor diagonal CP violating phases can account for the former and remarkably even for the latter case. This observation makes it simpler to speculate about which extensions with general flavor structure may also fit the data.